In a common form of a motor drive system, a motor produces a mechanical output, usually through a motor output shaft. The motor output shaft is mechanically linked to the driven component to transmit the mechanical output to the driven component. In principle, the motor and the driven component are perfectly aligned. In practice, however, there may be small misalignments either in the motor drive system as first assembled, or that develop during the course of service. The small misalignments may not be sufficiently large to cause the motor drive system to be inoperable, but they impose stresses on the motor and on the driven component that may damage bearings and other elements of the two devices.
A flexible coupling may be used between the motor output shaft and the driven component to transmit the power therebetween while flexing to accommodate misalignments between the motor output shaft and the driven component. The universal joint of an automobile drive train is a common example of a flexible coupling that allows the transmission of power between the motor and the driven wheels as the drive train misaligns during driving. In other circumstances, other types of flexible couplings such as bellows and spirally machined couplings are used.
While operable for many applications, the available flexible couplings are difficult or impossible to utilize for very small motor drive systems. For example, “micro-motors” with overall diameters of less than about 12 millimeters and shaft output diameters of less than about 3 millimeters are used in applications where driven components must be powered and the required power is low, and where the available size envelope is small. Optical fiber systems that employ multiple optical filters that must be mechanically moved into and out of an optical path are one such application. Universal joints and bellows cannot be economically manufactured in proportionately small sizes. The smallest economical universal joints and bellows are typically larger than the motors, and are also expensive to manufacture. Spirally machined couplings are made in this size range only with difficulty, and are also relatively expensive to fabricate.
There is a need for a mechanical flexible coupling that is suitable for use in small mechanical systems. The present invention fulfills this need, and further provides related advantages.